SOP: INSTRUMENTATION & SCADA | FRANCIS UNIT 1
SOP-CTRL-016 REV 2.1

INSTRUMENTATION & SCADA INTEGRITY

THE EYES OF THE SYSTEM

DRIFT RISK: HIGH

RTD TEMPERATURE VALIDATION

Resistance Temperature Detectors protect Babbit bearings from catastrophic melting.

  • Ice Bath (0°C) or Boiling (100°C) certified check.
  • Compare digital SCADA vs. analog mercury probe.
  • Tolerance: > 1.0°C deviation requires loop recalibration.

PRESSURE TRANSDUCER LOGIC

Determines Net Head and water hammer safety levels.

  • Zeroing: Atmospheric check @ 0.00 Bar (Drained).
  • Spanning: Compare vs. Analog Bourdon Gauge.
  • 4-20mA Scaling: Adjust PLC offset if drift is linear.

4-20mA LOOP INTEGRITY & SHIELDING

EMI INTERFERENCE (JITTER)

High-voltage cables parallel to signal lines cause 'Ghost Spikes'. If signal bounces >2%, check cabinet grounding.

LOOP HYGIENE

Tighten all 24VDC terminals. A loose lug is the #1 cause of false bearing trips.

FLOW METER HYGIENE

Silt and algae on electrode faces interfere with ultrasonic signals. Wipe sensing face annually with alcohol.

NEVER scratch electrodes with metal tools. Use soft cloth only.

SENSORY MAINTENANCE SCHEDULE

SYSTEM FREQUENCY TEST METHOD / REFERENCE
RTDs (Bearings) Monthly Analog Corelation vs mercury thermometers.
Pressure Transducers Annually (Dewatering) Zero-sum check at 0.00 Bar atmospheric.
Ultrasonic Flow Meter Annually Surface wiping & signal strength (dB) check.